﻿<html>
<head>
</head>
<body>
<script type="text/javascript">  
    var a,b;  
    (function(){  
        console.log(a);   // 1
        console.log (b);  // 2
        var a = b = 3;  
        console.log (a);  // 3
        console.log (b);  // 4
    })();  
        console.log (a);  // 5
        console.log (b);  // 6
</script>  
</body>
</html>

